What is biliary atresia?

Biliary Atresia: Definition and Management

Biliary atresia is a rare and severe inflammatory obliterative cholangiopathy that affects both extra- and intrahepatic bile ducts, resulting in obstruction of bile flow and, if untreated, leads to progressive conjugated hyperbilirubinemia, cirrhosis, and hepatic failure within 2 years of life. 1, 2

Clinical Presentation and Epidemiology

• Biliary atresia affects approximately 1 in 10,000-20,000 live births worldwide, with a higher prevalence in Asian countries 1
• Affected infants present with a clinical triad of conjugated jaundice, pale (acholic) stools, and dark urine, typically developing after 2-3 weeks of life 3
• Hepatosplenomegaly may be present on examination, with ascites developing later as liver disease progresses 1
• The disorder is rarely encountered in premature infants, suggesting a causative agent acting late in gestation 2

Pathophysiology and Etiology

• Biliary atresia involves obliteration or discontinuity of the extrahepatic biliary system, resulting in obstruction of bile flow 2
• Multiple potential etiologic mechanisms have been proposed:
  • Viral infections (particularly perinatal infections) are considered plausible triggers in many cases 2, 4
  • Genetic factors likely play important roles in disease susceptibility 2, 4
  • Environmental toxins have been suggested but not conclusively implicated 2
  • Immune dysregulation contributes to the progressive inflammatory cholangiopathy 3, 4
• The cholestatic injury triggers an intrahepatic fibrotic process beginning at birth and culminating in cirrhosis within months if untreated 1

Clinical Variants

• Several distinct variants of biliary atresia exist, including:
  • Isolated biliary atresia (most common form)
  • Biliary Atresia Splenic Malformation syndrome
  • Cat-eye syndrome
  • Cystic biliary atresia
  • CMV-associated biliary atresia 1

Diagnosis

• Prompt evaluation is essential for any infant older than 14 days with jaundice to determine if conjugated hyperbilirubinemia is present 2
• Diagnostic workup should rule out infectious, metabolic, and endocrine disorders 2
• The American Academy of Pediatrics recommends developing improved screening methods for earlier detection, as diagnosis before 2 months of age significantly improves outcomes 5
• If findings are consistent with biliary atresia, exploratory laparotomy and intraoperative cholangiogram should be performed expeditiously 2

Treatment

Kasai Portoenterostomy

• The American Association for the Study of Liver Diseases recommends Kasai portoenterostomy as the initial treatment of choice 5
• The procedure should be performed within the first 2 months of life by an experienced surgeon, as success rates significantly decrease when performed after 3 months 5
• When performed early by experienced surgeons, the Kasai procedure can result in prolonged survival in up to 70% of infants 5

Post-Kasai Management

• Ursodeoxycholic acid is commonly used post-operatively to promote bile flow 5
• Prophylactic antibiotics reduce recurrent cholangitis rates and improve survival 5
• Close monitoring for complications is essential, including:
  • Cholangitis
  • Portal hypertension
  • Variceal bleeding
  • Fat-soluble vitamin deficiencies
  • Growth failure 5

Liver Transplantation

• Liver transplantation is necessary in cases of:
  • Failure of the Kasai procedure
  • Development of intractable portal hypertension
  • Progressive liver failure
  • Delayed diagnosis 5
• Transplantation options include reduced-size deceased donor organ, living-related liver transplantation, and split liver transplantation 5
• One-year survival rates reach 93% with 5-year survival exceeding 85% 5

Prognosis

• Without treatment, biliary atresia is universally fatal, with death usually occurring within the first 1-2 years of life (median survival of 8 months) 5, 2
• If total serum bilirubin falls below 2 mg/dL within 3 months following Kasai procedure, up to 70% of patients may have prolonged transplant-free survival 5
• Approximately 25-35% of patients who undergo a Kasai portoenterostomy will survive more than 10 years without liver transplantation 2
• One-third of patients drain bile after Kasai but develop complications of cirrhosis requiring liver transplantation before age 10 2
• The remaining one-third of patients have inadequate bile flow following portoenterostomy and develop progressive fibrosis and cirrhosis 2
• Biliary atresia represents the most common indication for pediatric liver transplantation, accounting for more than 50% of cases 2